If the alignment of your set is off, such that the picture is rotated slightly (no more than about 1/4" from end to end), I've discovered that there is a way to correct this without opening the set up (at least for the 5687).
At the back of the set, along the bottom edge of the rear cover, there are two sets of two oval holes. One set is close to the centre, below the model/serial number sticker. The other set is before the bend on the right (when viewed from the back).
For each set, through one hole is a black screw head. Through the other hole you can see metal with a small hole, behind which is the centre of the head of a silver phillips screw.
The two black screws are all that is holding the tray of the light engine to the chassis of the set. The silver screws create bump stops that determine how deep each side of the light engine slides into the set. So, by changing the position of the bump stops you can slightly change the position of the light engine assembly, thus changing the rotation of the projected image on the screen.
To adjust your set, loosen off one of the black screws, adjust the silver screw in or out, then retighten the black screw. Check for alignment and repeat as necessary with either of the two sets. Be careful not to over tighten the black screws or you might bend the edge of the tray. You will need a screwdriver with a narrow shaft to get at the silver screw.
You can make the adjustments while the set is on and displaying a suitable test pattern. If you haven't got one, here's a test pattern that you can use. Load it onto a flash drive and display it using the WiseLink USB port.grid.jpg
Proceed at your own risk,